XDH and hyperuricemia: The basic principle of hyperuricemia treatment in the Japanese guidelines for the management of hyperuricemia and gout is the use of xanthine oxidase inhibitors (XOIs) (i.e., allopurinol, febuxostat) for “overproduction type” and uricosuric drugs (i.e., benzbromarone, probenecid, and bucolome) for “underexcretion type” [5].